In-line sulfur extraction process

Abstract

A method of removing hydrogen sulfide from a hydrocarbon stream such as natural gas or refinery off gas, including those from catalytic crackers, hydrocrackers, hydrotreaters, chemical plant processes, etc. Sulfur dioxide from an external source is directly introduced into the hydrocarbon stream to promote a Claus reaction to remove the hydrogen sulfide by converting it into elemental sulfur and water. The hydrocarbons in the stream are unaffected by the process.

I claim:  
     
         1 . A method for removing hydrogen sulfide from a hydrocarbon stream, said method comprising: 
 injecting sulfur dioxide from an external source into said hydrocarbon stream; and    forming elemental sulfur from said hydrogen sulfide and said sulfur dioxide in a Claus reaction.    
     
     
         2 . The method as in  claim 1 , said forming step occurring on a first catalytic reactor comprising a first catalyst bed.  
     
     
         3 . The method as in  claim 1 , further comprising: 
 heating said hydrocarbon stream prior to said sulfur dioxide injection step.    
     
     
         4 . The method as in  claim 3 , wherein said hydrocarbon stream is heated in the range of 260° F. and 300° F.  
     
     
         5 . The method as in  claim 1 , further comprising: 
 removing a vaporous elemental sulfur from a first desulfured hydrocarbon process stream leaving said first catalytic reactor.    
     
     
         6 . The method as in  claim 1 , further comprising: 
 forming elemental sulfur from said hydrogen sulfide and said sulfur dioxide in a second catalytic reactor comprising a second catalyst bed;    forming a first flush stream by heating a second desulfured hydrocarbon process stream leaving said second catalytic reactor; and    flushing said first catalyst bed with said first flush stream to wash said elemental liquid sulfur from said first catalyst bed.    
     
     
         7 . The method as in  claim 6 , further comprising: 
 heating said first flush stream.    
     
     
         8 . The method as in  claim 7 , wherein said first flush stream is heated in the range of 380° F.-420° F.  
     
     
         9 . The method as in  claim 6 , further comprising: 
 removing said elemental liquid sulfur from a sulfur rich wash stream, said sulfur rich wash stream resulting from said first flush stream washing said elemental liquid sulfur from said first catalyst bed.    
     
     
         10 . The method as in  claim 9 , further comprising: 
 removing an elemental vaporous sulfur from said sulfur rich wash stream.    
     
     
         11 . The method as in  claim 1 , wherein said first catalyst bed comprises a plurality of catalyst beads.  
     
     
         12 . The method as in  claim 11 , wherein said catalyst beads are chosen from a group consisting of alumina, activated charcoal, and aluminum carbonate.  
     
     
         13 . The method as in  claim 6 , further comprising: 
 forming a second flush stream by heating a first desulfured hydrocarbon process stream leaving said first catalytic reactor, and    flushing said second catalyst bed with said second flush stream to remove said elemental liquid sulfur.    
     
     
         14 . A method for removing hydrogen sulfide from a hydrocarbon stream, said method comprising: 
 injecting sulfur dioxide from an external source into said hydrocarbon stream; and    forming elemental sulfur from said hydrogen sulfide and said sulfur dioxide in a Claus reaction.    
     
     
         15 . The method as in  claim 14 , further comprising: 
 passing said hydrocarbon stream through a liquid sulfur recovery unit to remove said elemental sulfur.    
     
     
         16 . The method as in  claim 14 , further comprising: 
 passing said hydrocarbon stream through a catalytic reactor; and    subsequently passing said hydrocarbon stream through a liquid sulfur recovery unit to remove said elemental sulfur.